529
FXUS65 KCYS 041731
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1131 AM MDT FRI SEP 4 2026
KEY MESSAGES
- RED FLAG WARNING IN EFFECT FOR CONVERSE AND NIOBRARA
COUNTIES.
- WARMING AND DRYING TREND EXPECTED THROUGH THE END OF THE WEEK.
- PRECIPITATION CHANCES RETURN FOR THE BEGINNING OF NEXT WEEK.
SHORT TERM /THROUGH SATURDAY NIGHT/
ISSUED AT 532 AM MDT FRI SEP 4 2026
A WEAK SURFACE LOW IS PUSHING THROUGH THE AREA THIS MORNING SPARKING
SOME WEAK THUNDERSTORMS FOR THE NEBRASKA PANHANDLE. THE RAP EXTENDS
A FINGER OF 300 JOULES OF CAPE ACROSS THE NORTHERN PERIPHERY OF THIS
LOW HELPING TO SUSTAIN THESE WEAK THUNDERSTORMS. THEY HAVEN'T BEEN
PRODUCING A LOT OF RAIN AS THE SCOTTSBLUFF ASOS REPORTED ONLY A
TRACE OF RAIN AND ALLIANCE ONLY REPORTED LIGHTNING AS THESE SHOWERS
PASSED OVER THEM. THIS AFTERNOON AND EVENING AN ISOLATED SHOWER WILL
BE POSSIBLE. ANOTHER WEAK SHORTWAVE WILL BE PUSHING THROUGH AROUND
PEAK HEATING AT 21/22Z. BESIDES THE SHORTWAVE PROVIDING SOME
SYNOPTIC SUPPORT, THE CONVECTIVE TEMPERATURE AROUND 90 WILL LIKELY
BE REACHED IN AREAS EAST OF THE I-25 CORRIDOR. ALSO ACCOMPANYING
THIS SHORTWAVE IS A STREAM OF VORTICITY THAT WILL BE KIND OF MOVING
ENE FROM LARAMIE COUNTY AND INTO THE PANHANDLE. DESPITE THE SYNOPTIC
SUPPORT GIVEN TO THE STORMS THE MODELS AREN'T TOO EXCITED ABOUT
TODAY. THE REASON MAY BE IS THAT THERE IS VERY LITTLE MOISTURE AT
THE SURFACE. MODEL SOUNDINGS SHOW A PRETTY STOUT INVERTED V SOUNDING
BUT THE MODELS ALSO SHOW THE AFTERNOON RH VALUES TO HOVER BETWEEN 15
TO 20 PERCENT. SO WITH LITTLE MOISTURE AND ONLY DECENT SYNOPTIC
SUPPORT TODAY MAY AGREE WITH THE MODELS SHOWING AN ISOLATED TO
SLIGHTLY SCATTERED THUNDERSTORM DAY. SPC WOULD ALSO AGREE WITH THE
MODELS IN THIS PARTICULAR LACK LUSTER OF A DAY AS OUR PORTION OF THE
INTERMOUNTAIN WEST IS ONLY COVERED BY A GENERAL THUNDER WHERE
LIGHTNING WILL BE THE MAIN THREAT. ALSO CONSIDERING HOW DRY THE
SURFACE WILL BE THERE WILL BE ALSO A SLIGHT RISK FOR DRY THUNDER.
THE HRRR AND NAM NEST HAVE LINGERING SHOWERS LASTING THROUGH TO
SATURDAY MORNING. HOWEVER, SHOWERS UNTIL 11PM MAY BE MORE REASONABLE
AS THE RAP SHOWS THE WAVE MOVING OUT OF THE AREA BY 11PM WITH ALMOST
NO ENERGY LEFT FOR THE STORMS TO UTILIZE. SATURDAY, WILL BE KIND OF
THE SAME STORY. THE LOW PRESSURE SYSTEM JUST OFF THE WEST COAST WILL
SEND ANOTHER SHORTWAVE THROUGH OUR REGION. THE MOISTURE CONTENT WILL
BE MARGINALLY BETTER THAN TODAY AS THE LOW PRESSURE SYSTEM HELPS
FUNNEL MOISTURE FROM THE PACIFIC OCEAN AND INTO THE ROCKY MOUNTAINS.
THE HI-RES MODELS ARE MORE EXCITED ABOUT THE STORM SITUATION ON
SATURDAY THAN TODAY. THE RAP PLACES ABOUT 1500 JOULES ALONG THE
EASTERN PORTION OF LARAMIE COUNTY AND THE MAJORITY OF THE PANHANDLE.
THERE IS SOME VORTICITY SUPPORT WITH SATURDAY BUT THE DECIDING
FACTOR FOR SATURDAY WILL BE HOW MUCH MOISTURE IS THE LOW ABLE TO
SEND INTO OUR AREA. THE BEST TIMING FOR SHOWER/STORM DEVELOPMENT
LOOKS TO BE AFTER 3PM FOR OUR AREA WITH THE MODELS QUICKLY PUSHING
THE STORMS OUT OF OUR AREA AROUND 7PM. HOWEVER, THE MAJOR VORTICITY
SUPPORT DOES COME LATER INTO THE EVENING. SO THE MOST LIKELY
SCENARIO LOOKS TO BE SOME SCATTERED SHOWERS WITH A COUPLE OF
POTENTIAL SUPERCELLS. SPC HAS DRAFTED A MARGINAL RISK FOR SEVERE
THUNDERSTORMS IN THE NEBRASKA PANHANDLE WERE THE ENVIRONMENT IS EVER
SO SLIGHTLY BETTER FOR SUSTAINING THUNDERSTORMS.
LONG TERM /SUNDAY THROUGH THURSDAY/
ISSUED AT 532 AM MDT FRI SEP 4 2026
SUNDAY, THE LOW OVER THE PACIFIC NORTHWEST STARTS TO PUSH
AGAINST OUR UPPER LEVEL RIDGE AS IT TRIES TO PUSH FURTHER INTO
THE INTERIOR OF WESTERN UNITED STATES. WHEN THIS OCCURS MORE OF
THE MONSOONAL MOISTURE WILL FEED OVER OUR REGION PRIMING THE
INTERMOUNTAIN WEST FOR MORE STORM ACTIVITY. THE STORM COVERAGE
WILL SLOWLY INCREASE AS WELL AS MORE MOISTURE FEEDS INTO THE
REGION. THE SYSTEM WILL INCH TOWARDS THE INTERMOUNTAIN WEST AND
START TO FLATTEN OUR RIDGE.
THE TREND OF SHOWERS AND THUNDERSTORMS CONTINUE THROUGH MONDAY
AND TUESDAY AS THE STUBBORN TROUGH TO THE NORTHWEST FINALLY
EJECTS INTO THE CENTRAL PLAINS. WHILE MOISTURE WILL REMAIN
HIGH, A LOBE OF DRIER AIR ASSOCIATED WITH A RIDGE TO THE EAST
MAY BE PULLED IN AHEAD OF THE TROUGH WHICH WOULD REDUCE RAIN
POTENTIAL. HOWEVER, SINCE THE TROUGH IS EJECTING IT IS POSSIBLE
THAT CYCLOGENESIS OCCURS NEARBY INCREASING THE SEVERE WEATHER
POTENTIAL. SOME MACHINE LEARNING MODELS ARE HIGHLIGHTING AN
UPTICK IN THAT POTENTIAL FOR THE NEBRASKA PANHANDLE AREA.
THE DETAILS OF HOW THIS UNFOLDS WILL BE IRONED OUT AS WE GET
CLOSER.
THE REMAINDER OF THE LONG TERM IS IN A DRYING TREND. THE
RIDGE NOSES IN. THIS WOULD NOT COMPLETELY SHUT DOWN STORM
ACTIVITY.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1125 AM MDT FRI SEP 4 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE FORECAST
PERIOD. WINDS ARE BEING OBSERVED HIGHER THAN PROGGED IN MODEL GUIDANCE
AND PREVIOUS FORECASTS. AS SUCH A BUMP IN WINDS WAS ADDED IN THE
SHORT TERM GROUP FOR SOME TERMINALS. A FEW AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS ARE POSSIBLE IN HIGH
RESOLUTION MODEL SOLUTIONS. THE GREATEST POTENTIAL EXISTS AT
KCYS WHERE NEARBY STORMS COULD PRODUCE LIGHTNING AND VARIABLE
GUSTS. A SMALLER CHANCE AT KCDR OF STORMS AS WELL AFTER 21Z.
OUTSIDE THE ISOLATED CONVECTION, WINDS SHOULD CALM AND REMAIN
WEAK GOING INTO THE EVENING AND INTO TOMORROW, BECOMING VARIABLE
AT TIMES. INCREASING CLOUD COVERAGE LATE IN THE FORECAST PERIOD
CAN BE EXPECTED AHEAD OF THE NEXT SHORTWAVE.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...MM
LONG TERM...MM
AVIATION...RV
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